Impregnating method



Aug. l0, 1943. .LA LIGNIAN IMPREGNATING METHOD Original Filed July 13,1939 MR, uw H f5, m QQ; I. ri /M E ..5 E afm mm W@ NN -d o M n g QN .QRN\ F ||J J .H1 IIIJ l Nw m Patented Aug. 10, 1943 g UNITED STATES PATENT.oFFlcE R mrltEGlrzZizarErili-m l i Jean A. Hgnian, Dayton, Ohio,assigner to General Motors Corporation, Detroit, Mich., a cor- Dotationof Delaware original application July 13, 1939, serial No.

284,222. `\Divided and this application November 14, 1940, Serial No.365,644

3 Claims.

This invention relates to an impregnating apparatus and is particularlyconcerned with the method' and apparatus for continuousy impregnatingporous strip material.

An object of the invention is to provide a method and apparatus forvcontlnuously'impregnating porous metal strip material wherein the stripis mechanically operated upon for dislodging occluded air in the porousstructure thereof during the impregnatlng operation.

In carrying out the above object it is a further object, in some cases,to vibrate the strip for dislodging occluded air in the porous structurethereof.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

Fig. 1 is a cross-sectional view of a preferred type of impregnatingapparatus.

Fig. 2 is a sectional view taken along the lines 2-2 of Fig. 1.

Fig. 3 is a fragmentary enlarged view of a continuous strip of metalhaving a sintered highly porous metal layer bonded thereto, and

Fig. 4 is a view showing another type of vibration mechanism.

Referring to the drawing and more specically to Fig. 1, a continuousmetal strip 20 having a. sintered highly porous metal layer 22 bondedthereto is inserted into an elongated opening 24 in an impregnatingapparatus 23. Adjacent the opening 24 and directly above the continuousstrip 20 is a flux spraying jet 26 which ejects a continuous stream offlux against the sintered highly porous metal layer 22 on the strip 20.

A leg 28 of the impregnating apparatus 23 contains molten babbitt, orany suitable molten bearing metal or composition 30, into which thecontinuous strip V20 is passed after going through opening 24. Whilepassing through the molten babbitt the sintered highly porous metallayer 22 on strip 20 soaks up and becomes impregnated with the bearingmaterial 30. 'I'he strip 20 then passes under a set of rollers 32 andover a second set of rollers 34 into a vacuum dome 50, which isevacuated by a vacuum pump, not shown, through the conduit 52. Uponentering the vacuum dome 50 the strip 20 is mechanically operated uponby a vibrating means 54, said yibratlng means being motivated in asuitable manner to rotate at high speeds and to vibrate the strip 20 insuch a manner as to dislodge any l (Cl. 117-114) occluded air in theporous metal layer on strip 20. From the vibrator 54, thestrip 20 passesover rollers 36 and under rollers 38 into leg 40 where it again entersthe bath of molten bearing material, and the highly porous metal layeris further impregnated. The strip 20 leaves the impregnatingA apparatusthrough an opening 42 provided therefor in the leg 40. It will be notedthat the rollers 32, 34, 36 and 38 are so arranged as to permit thepassage of strip material which may be of relatively heavy or of thickcross section. In this manner continuous strips of any desirable weightor thickness may be impregnated without permanent deformation.

In order' to prevent the molten bearing material 30 from flowing throughthe openings 24 and 42 in the legs 28 and 40, respectivey, of theimpregnating apparatus 23, there have been provided water cooling jets44 and 46 adjacent the openings 24 and 42, which cooling jets cause acool spray to be directed against the impregnatlng device near theirrespective openings to substantially freeze the molten babbitt, therebypre- .venting its outward flow through the said openings. A reservoir 6Dis provided in the leg 28, which reservoir contains the excess moltenbabbitt 30 and is Supplied from a tank 62 through conduit 64. Likewise,a similar reservoir 'l0 is provided in the leg 40 and also contains themolten babbitt 30 and in this instance is supplied from a tank 12through conduit 14. It is to be understood, however, that reservoirs 6l)and 10 may be connected by a conduit, thereby eliminating supply tank'I2 and its conduit 14, Hoods 56 .and 66 have been provided overreservoirs and 10 respectively to carry off obnoxious vapors. The entireapparatus 23 is maintained at an elevated temperature above the meltingpoint of the impregnant, in the present instance 700 F. for a 625 M. P.babbitt. The heating can be accomplished by any conventional method.

It will be observed that the level of the molten babbitt in dome 50 issomewhat higher than that in reservoirs 60 and 10. This is due to thefact that dome 50 is substantially completely evacuated by the vacuumpump, and the fact that the molten-babbitt in reservoirs 60 and 10 isexposed to atmospheric pressure. In this instance the babbitt level indome 50 is approximately 2.97 feet higher than that in reservoirs 60 andl0 at standard conditions at sea level, due to the specific gravity ofthe babbitt which is about 11.43. It will further be noted that when thestrip 20 enters the vacuum dome 50, it has been raised out of the moltenbearing material by its passage over rollers 34, vibrator 54 and rollers36, and does not re-enter the bath until it passes over and beyondrollers 36. By reason of this fact the strip 20 is entirely exposed onall sides as it is contacted by vibrator 54, thus assuring absolutedislodging of any occluded air in the sintered highly porous metal layer22, bonded to the strip 20 before it is further impregnated by themolten babbitt in leg 40.

Referring specifically to Fig. 2, one form of vibrator mechanism 54 isshown comprising a. roller I6 having projections 18 thereon and disposedto vibrate strip 20 when the said strip contacts the projections in itspassage through vacuum dome 50. The roller is fixed between a pair ofuprights 19 in the impregnating apparatus 23, and is motivated by anysuitable means to rotate at high speeds.

Fig. 4 shows a modied vibrator mechanism wherein a pair ofelectro-magnets and |02 are positioned on either side of the strip 20.The magnets |00 and |02 are electrically connected in series and areenergized from an A. C. source. Thus, due to the proximity of the stripand the change in direction of the current, the strip is vibratedbetween the magnets. The amplitude of stroke is controlled by theseparation of the magnets while the frequency is directly controlled bythefrequency of the A. C. source. The strip 20 with the layer 22 thereoncan be formed in any suitable manner, one of such methods beingdisclosed in ther Koehring Patent 2,198,253, April 23, 1940.

Still another modification utilizes a. single magnetic solenoid which isenergized by pulsating D. C. source which in turn mechanically vibratesthe strip.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsasaasra might be adopted, al1 coming within the scope of the claimswhich follow.

This application is a division of application Serial No. 284,222 filedJuly 13, 1939, now Patent No. 2,293,840 dated Aug. 25, 1942.

What is claimed is as follows:

1.` In a continuousmethod of impregnating porous metallic stripmaterial, the steps comprising; immersing the porous strip material inan impregnating fluid, removing the strip material from the impregnatingfluid in a chamber held at pressures less than atmospheric pressure,vibrating the strip in said chamber for removing occluded air from theporous material of the strip, and then further impregnating the strip byagain immersing the strip in the impregnating uid prior to exposure toatmospheric conditions.

2. In a continuous method of impregnating porous metallic, stripmaterial, the steps comprising; immersing porous strip material in`animpregnating fluid and mechanically vibrating for dislodging theoccluded air from the porous structure of the strip while simultaneouslyreducing the air pressure surrounding said strip, said steps takingplace during a portion of said impregnation step only whereby theimpregnated fluid will substantially completely iill the pores of theporous strip.

3. In a continuous method of impregnating porous metallic stripmaterial, the steps comprising; immersing the porous strip in animpregnating fluid, evacuating the strip after partial impregnationthereof, simultaneously mechanically vibrating the strip to aid inremoving occluded air therefrom and again immersing the.

evacuated strip in the impregnating fluid a portion of which ismaintained at atmospheric pressure whereby substantially completeimpregnation of the porous strip materialis accomplished.

JEAN A. LIGNIAN.

